Windows Azure SQL Database also known as SQL Server Data Services or simply SQL Azure is a Microsoft’s cloud services that offers a capabilities on Microsoft SQL Server 2012 (such as Amazon S3 and Amazon Relational Database Services), as part of the Azure Services Platform. Windows Azure SQL Database uses special version of Microsoft SQL Server as its backend that provides high availability by storing multiple copies of databases i.e. flexible range and fast. Windows Azure SQL Database is hosted on Microsoft data centers on the hardware that is owned, hosted and maintained by Microsoft. Unlike other cloud-based databases, Windows Azure SQL Database allows users to write and execute queries against stored data that can either be structured or semi-structured or unstructured documents. Windows Azure SQL Database presents a subset of the full SQL Server functionality that includes specific subset of the data types (includes string, number, date and boolean), tables, primary keys, stored procedures, views and much more. Applications can use Windows Azure SQL Database in the same way they use SQL Server Database Engine because Windows Azure SQL Database use T-SQL as a query language and Tabular Data Stream (TDS) protocol for accessing services over the Internet.

Check out my article here, which presents an overview of the architecture and steps to configure and manage Microsoft Windows Azure SQL Database.